The "\n" were there so that the string fits in the button widget, and
I'm pretty sure they are still needed (see how the display of the
translation for "Upgrade from ISO" in fr_CA is buggy, for example)
=> reverted that part. In general, please don't drop manual formatting
unless you're 100% certain that it's obsolete and now useless :)
Also, IIRC the "&&" was useful for something (I don't remember what),
and I see that a few other PO files (that I've tested and work fine)
have it => re-added.